O2 Sensor Signal Shorted to Heater Circuit Bank 1 Sensor 3
The P2233 code indicates that the oxygen sensor signal circuit for Bank 1 Sensor 3 (downstream sensor after the catalytic converter) is shorted to the heater circuit. This typically occurs due to damaged wiring, a shorted sensor, or a faulty heater circuit. The short can cause incorrect voltage readings, affecting fuel trim and emissions control.
01. Most Common Causes
- Damaged or melted wiring harness near exhaust
- Faulty oxygen sensor (internal short)
- Corroded or loose connector
- Heater circuit short to ground or power
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Failed emissions test
- Possible rough idle or hesitation
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P2233 and check freeze frame data.
Step 2: Visually inspect the O2 sensor wiring and connector for damage, melting, or corrosion.
Step 3: Disconnect the sensor and measure resistance between heater pins (should be 3-10 ohms).
Step 4: Check for continuity between signal and heater circuits; if shorted, repair or replace wiring.
Step 5: If wiring is intact, replace the oxygen sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally safe to drive short distances, but continued driving may cause poor fuel economy and potential damage to the catalytic converter. It is recommended to diagnose and repair promptly.
How much does it cost to fix?▼
The cost typically ranges from $150 to $300, including parts (O2 sensor) and labor. DIY replacement can be cheaper, around $50-$100 for the sensor.